Regional cerebral blood flow in Alzheimer's disease: comparison between short and long-term donepezil therapy.

OBJECTIVE: Treatment with donepezil improves cognitive function of patients with Alzheimer's disease (AD) when compared to a placebo-controlled group. The purpose of this study was to investigate changes in regional cerebral blood flow (rCBF) of AD patients in short-term and long-term treatment with donepezil. METHODS: rCBF was measured by N-isopropyl-p-123I-iodoamphetamine (IMP) autoradiography method. CBF measurements were performed in 17 AD patients before treatment and after 3 months (short-term therapy) and 1 year (long-term therapy). Regions of interest were set at cerebral cortex and cerebellar hemisphere. We used absolute CBF and relative CBF expressed as ratio to cerebellar CBF. RESULTS: Significant increases in relative rCBF were noted in the frontal, parietal and temporal lobes at the end of short-term therapy. rCBF was decreased after the long-term therapy, whereas rCBF was still increased to a slight extent, as compared with the pre-treatment levels. Absolute rCBF showed minimal change and a tendency to decline. CONCLUSION: Relative rCBF significantly increased in the short-term donepezil therapy, while following the long-term therapy, rCBF decreased to the pre-treatment level.

FDG-PET in a case of multiple bone metastases of gastric cancer.

F-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is useful for surveys to detect bone metastasis because of its greater specificity than bone scintigraphy. However, FDG-PET is also known to yield false-positive results in acute fractures and inflammatory lesions, and distinguishing between benign and malignant lesions is difficult, even when semiquantitative methods are used. We report a case of multiple bone metastases of gastric cancer. One of the bone lesions that was positive for FDG uptake was benign, suggesting that FDG-PET can yield false-positive results.

Do short-time SPECT images of bone scintigraphy improve the diagnostic value in the evaluation of solitary lesions in the thoracic spine in patients with extraskeletal malignancies?

OBJECTIVE: Single photon emission computed tomography (SPECT) images provide many details of the anatomical structure. Also about bone scintigraphy, there are many reports of the improvement of diagnosis by SPECT images. Although SPECT is useful, it requires much time. So to perform SPECT for all cases is difficult in the clinical situation. Recently, due to technical improvements in gamma cameras, we can get SPECT images in a short time. We examined diagnosis of solitary hot spots of thoracic spine in cancer patients using short-time SPECT. And we considered whether short-time SPECT contributes to the precise diagnosis of the lesion. MATERIAL AND METHODS: We performed bone scintigraphy image acquisition and both planar and short-time SPECT of the chest. Short-time SPECT was acquired in 6 minutes. We selected 36 cases with malignancy, whose bone scintigraphy demonstrated a solitary accumulation hot spot in the thoracic spine. Three experienced radiologists in nuclear medicine and 4 beginners diagnosed the images. They interpreted planar, short-time SPECT and maximum intensity projection (MIP) view of the chest of each case. The observers' response data were analyzed with receiver operating characteristic (ROC) curve analysis. RESULTS: Of the three types of images, the Az (the area under ROC curve) values of short-time SPECT were the highest in all the observers except for only one beginner. Compared with experienced observers, beginners scored lower Az values of short-time SPECT. MIP images were constructed using SPECT data, but the Az values of MIP images were not higher than those of planar images. As to diagnosis, beginners tended to interprete most of the accumulations as metastatic lesions. CONCLUSION: Short-time SPECT can be helpful to some degree, but to provide greater benefit, the observers require considerable exercise and experience.

123I-Metaiodobenzylguanidine uptake in the nape of the neck of children: likely visualization of brown adipose tissue.

UNLABELLED: The distribution of radioiodinated metaiodobenzylguanidine (MIBG) has been studied primarily in patients with neuroendocrine tumors-in pediatrics, particularly with neuroblastomas. Sometimes, symmetric accumulation in which no tumor is identified is seen in the nape-of-the-neck region. We estimated visually whether accumulation was found in the nape of the neck and studied the characteristics of the accumulation. METHODS: Retrospectively, we investigated 266 (123)I-MIBG scintigraphic studies performed on pediatric patients who had been treated for neuroendocrine tumors or who were suspected of having such tumors. RESULTS: Accumulation in the nape of the neck was seen in 32 of 266 studies (12%); in none of these cases was the accumulation identified as a tumor by other imaging modalities or follow-up studies. In the same individuals, the accumulation varied and it was observed more often during winter. CONCLUSION: Symmetric (123)I-MIBG accumulations in the nape-of-the-neck region observed in children are thought to be related to the uptake in brown adipose tissue.

Pattern of 111In-chloride bone marrow scintigraphy in myelodysplastic syndrome; comparison with clinical characteristics.

111In-chloride bone marrow scintigraphy (bone marrow scintigraphy) was performed in patients with myelodysplastic syndrome (MDS), tracer accumulation was classified into patterns, and the relationship between the accumulation patterns and prognostic factors was investigated to assess the usefulness of bone marrow scintigraphy. The subjects were 14 patients diagnosed with MDS. Accumulation of the bone marrow scintigraphy tracer was classified according to the degree of accumulation in the axial bone marrow and peripheral expansion. International Prognostic Scoring System (IPSS), which are frequently used for prognostic evaluation of MDS, and conversion to leukemia were investigated in prognostic factors. We also investigated the relationship between enlargement of the liver and spleen and the prognostic factors. The accumulation patterns were as follows: pattern I, The normal accumulation pattern (2 cases); pattern II, the expanded accumulation pattern (6 cases); pattern III, low accumulation pattern (5 cases); and pattern IV, heterogeneous accumulation pattern (1 case). The relationships between the two prognostic factors and accumulation patterns were investigated, and the prognosis was found to be significantly poorer in the patients with the low accumulation pattern than the expanded accumulation pattern. Enlargement of the liver and spleen was not significantly correlated with the prognostic factors.

Pitfalls of FDG-PET for the diagnosis of osteoblastic bone metastases in patients with breast cancer.

PURPOSE: The purpose of this study was to investigate the pitfalls of using 2-[18F]-fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) for the evaluation of osteoblastic bone metastases in patients with breast cancer by comparing it with (99m)Tc-hydroxymethylene diphosphonate bone scintigraphy. METHODS: Among the 89 breast cancer patients (mean age 59+/-15 years) who had undergone both FDG-PET and bone scintigraphy within 1 month between September 2003 and December 2004, 55 with bone metastases were studied. The bone metastases were visually classified by multi-slice CT into four types according to their degree of osteosclerosis and osteolysis-osteoblastic, osteolytic, mixed and invisible-and compared in terms of tracer uptake on FDG-PET or bone scintigraphy and SUV(mean) on FDG-PET. Differences in the rate of detection on bone scintigraphy and FDG-PET were analysed for significance by the McNemar test. RESULTS: The sensitivity, specificity and accuracy of bone scintigraphy were 78.2%, 82.4% and 79.8% respectively, and those of FDG-PET were 80.0%, 88.2% and 83.1%, respectively, revealing no significant differences. According to the CT image type, the visualisation rate of bone scintigraphy/FDG-PET was 100%/55.6% for the blastic type, 70.0%/100.0% for the lytic type, 84.2%/94.7% for the mixed type and 25.0%/87.5% for the invisible type. The visualisation rates of bone scintigraphy for the blastic type and FDG-PET for the invisible type were significantly higher. The SUV(mean) of the blastic, lytic, mixed and invisible types were 1.72+/-0.28, 4.14+/-2.20, 2.97+/-1.98 and 2.25+/-0.80, respectively, showing that the SUV(mean) tended to be higher for the lytic type than for the blastic type. CONCLUSION: FDG-PET showed a low visualisation rate in respect of osteoblastic bone metastases. Although FDG-PET is useful for detection of bone metastases from breast cancer, it is apparent that it suffers from some limitations in depicting metastases of the osteoblastic type.